Chain cutter

ABSTRACT

A compact chain cutting apparatus for automatically shearing and opening a chain link of a selected thickness in one operation is disclosed. The apparatus includes a housing, a first shearing member, a second shearing member, and an electro-hydraulic actuator system. The first shearing member is mounted to the housing. The second shearing member is pivotally mounted to the housing for movement to exert, in cooperation with the first shearing member, shearing and bending forces upon the chain link. The electro-hydraulic actuator system cooperates with the second shearing member to move automatically the second shearing member to shear and to bend the chain link, thereby defining an opening in the chain link greater than the thickness of the link.

FIELD OF THE INVENTION

The present invention relates generally to a chain cutting apparatus,and more particularly to an automatically operated,electro-hydraulically actuated apparatus for cutting and opening chainlinks.

BACKGROUND OF THE INVENTION

In retail establishments selling chain and in light manufacturingfacilities, chain is generally cut by either sawing through the chainlinks or by using a cold forming pincher-type tool commonly called a“bolt cutter.” While these techniques are adequate for cutting smallgauge chains, the same techniques raise a number of practical problemsin cutting larger gauge chains.

In the case of sawing through a link, the most serious problem arisesfrom the necessity to support the chain link rigidly in a vice or otherclamping apparatus while a hack saw is employed to saw through the linkat a point along its circumference. If only one cut is made through thelink, some means of bending the link must be employed in order to createan opening between the severed ends large enough to allow the cut linkto be disengaged from the connecting links. This additional operationnecessarily involves the use of a second tool, whether it be alever-type instrument to pry open the link or an impact-type instrumentto hammer the link open. The bending operation can be eliminated bysawing through the link at a second point, thereby bisecting the link.This second cutting operation is time consuming and difficult whendealing with heavy gauge chains.

When a bolt cutter or similar tool is used, again it is necessary eitherto cut the link in two places or employ supplemental means to bend thecut link open. Another problem arises because of the difficulty inholding the tool; namely, the risk that the cutting edges will beabused.

Moreover, sawing cable or wire rope to cut it causes fraying at the cutends. Cutting cable or wire rope by cold forming techniques is onlyeffective if the working edges of the “bolt cutter” are maintainedadequately to sever the individual strands of the cable. It is oftendifficult to so maintain the edges when, as a result of economy, thesame tool is used on chain, bolts, cable, and other like materials.

A manually operated, hydraulically actuated apparatus for both cuttingand opening chain links, for example, as shown and described in U.S.Pat. No. 3,996,782, has been used to solve some of the problems of theprior art. Although such a device has many desirable features andadvantages, there remain certain problems with this cutter.

For example, the manual chain cutter using a manual pump jacks is proneto fluid leakage, labor intensive to operate, slow and under-powered forcutting certain sizes of chain link. The seals in the apparatus have atendency to wear out and allow fluid leakage to occur. In operation, theapparatus typically requires priming before the apparatus can be used tocut. When cutting a chain link of larger gauge, the pump jack often mustbe pumped over fifty times in order to successfully cut and open thechain link. Furthermore, maintaining the manual pump jacks can becumbersome.

In view of the foregoing, there exist various needs in the art. One suchneed is for a compact, durable chain cutter which provides uniform,consistent speed and power during cutting. A further need exists for achain cutter that is fast and easy to operate. Additionally, it would bedesirable for the chain cutter to be safe to use and operable only byauthorized personnel.

SUMMARY OF THE INVENTION

The present invention addresses the foregoing and other needs byproviding an automatically-operated, hydraulically-actuated apparatusfor cutting and opening chain links. In one aspect of the presentinvention, there is provided an automatic apparatus for shearing andbending a chain link of a selected thickness. The apparatus includes ahousing. A first shearing member is mounted to the housing. A secondshearing member is pivotally mounted to the housing for movement toexert, in cooperation with the first shearing member, shearing andbending forces upon the chain link. An electro-hydraulic actuator systemis provided to move automatically the second shearing member to shearand to bend the chain link, thereby defining an opening in the chainlink greater than the thickness of the link.

The first shearing member has a shearing surface defining a shearingplane and terminating in a first shearing edge. The first shearingmember includes a jaw. The jaw has a primary bearing surface to exertshearing and bending forces upon the chain link and a secondary bearingsurface for preventing unrestrained twisting during the shearing andbending operations. The jaw defines an opening configured to accommodatethe thickness of the chain link.

The second shearing member has a shearing surface disposed substantiallyparallel to the shearing plane and terminating in a second shearingedge. The second shearing member includes a primary bearing surface toexert shearing and bending forces upon the chain link. The secondshearing member is arranged with the first shearing member for relativeshearing action along the shearing plane between the primary bearingsurfaces and the shearing edges.

The electro-hydraulic actuator system requires no manual actuation forceinput. The actuator system includes a hydraulic cylinder, a pump, areservoir, and an electric motor. The hydraulic cylinder has a base anda driving rod with a distal end. The base is pivotally mounted to thehousing. The distal end of the rod is mounted to the second shearingmember for moving the second shearing member. The pump is fluidlyconnected to the cylinder for driving the cylinder. The reservoir has aquantity of hydraulic fluid. The pump is fluidly connected to thereservoir for drawing the hydraulic fluid from the reservoir and pumpingthe hydraulic fluid under pressure to the hydraulic cylinder. The motoris operatively connected to the pump for selectively driving the pump.

Significantly, the actuator system requires no priming before operationand moves the second shearing member smoothly and consistently through asubstantially uniform stroke at a steady velocity.

Advantageously, the present invention provides an automated apparatusfor cutting and opening in a single operation a chain link, therebyminimizing the time, energy, and equipment required. Furthermore, theapparatus is capable of cutting not only chain but also bolts, wirerope, and the like.

Advantageously, the present invention provides an automated chaincutting apparatus which is compact, powerful enough to operate on chainlinks of heavy—as well as light—gauge, and composed of relativelyinexpensive components, to fulfill the cutting needs of retailestablishments and light manufacturing facilities.

By eliminating the need to cut the chain link by manual exertion, thepresent invention can be used by a wide range of users and requires verylittle physical exertion on the part of the user. The chain cuttingapparatus can be about six times as fast as a prior art manual chaincutting apparatus in cutting a chain link. Furthermore, no priming isrequired before operating the apparatus.

As a further feature, the chain cutting apparatus can be provided with akeyed switch for operating the motor. Advantageously, the switch can bebiased to an off position such that the apparatus stops running once theoperator releases the key.

These and other objects and advantages, as well as additional inventivefeatures, of the present invention will become apparent to one ofordinary skill in the art upon reading the detailed description, inconjunction with the accompanying drawings, provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an automatic chain cutting apparatusaccording to the present invention;

FIG. 2 is a fragmentary front elevational view of the chain cuttingapparatus of FIG. 1 with a portion of the housing removed;

FIG. 3 is a side elevational view of a first, stationary shearing memberof the chain cutting apparatus of FIG. 1;

FIG. 4 is an end elevational view of the stationary shearing member ofFIG. 3;

FIG. 5 is a side elevational view of a second, movable shearing memberof the chain cutting apparatus of FIG. 1;

FIG. 6 is a an end elevational view of the movable shearing member ofFIG. 5;

FIG. 7 is a fragmentary front elevational view as in FIG. 2 of a supportsystem of the chain cutting apparatus of FIG. 1;

FIG. 8 is a side elevational view of a mounting block of the chaincutting apparatus of FIG. 1

FIG. 9 is a fragmentary front elevational view of another embodiment ofa support system for a chain cutting apparatus according to the presentinvention;

FIG. 10 is a side elevational view of a cutter keeper of the supportsystem of FIG. 8;

FIG. 11 is a front elevational view of the chain cutting apparatus ofFIG. 1 with a portion of the housing removed;

FIG. 12 is a cross-sectional view taken along line 12-12 of FIG. 11illustrating the operational parts of the chain cutting apparatus; and

FIG. 13 is a diagrammatic general schematic view of an ignition systemfor a motor of the chain cutting apparatus of FIG. 1.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Shown in the drawings is an illustrative apparatus for cutting andopening chain links and bolts and for severing steel wire sold, forexample, in hardware stores and material supply depots. The illustrativechain cutter shown herein improves upon and solves some of the drawbacksassociated with the chain cutter shown and described in U.S. Pat. No.3,996,782, filed Jul. 17, 1975, and entitled “Chain Cutting Apparatus,”which is incorporated herein in its entirety by reference.

The instant apparatus employs a pair of shearing members which interactto first shear a link of chain at a point along its circumference andthen to bend the link. The latter operation of opening the link topermit the disengagement of the severed link is more efficient, energywise, than generating a second cut to facilitate removal of the link. Toallow a wide range of operators to use the chain cutting apparatus, anautomatic actuator system is provided to operate automatically at leastone of the shears to perform the shearing and bending operations. Theapparatus is self-contained, lightweight, and, requiring only a 110VAC-convenience outlet for its power source, readily transportable. Thesmall size of the apparatus, approximately one half cubic foot, forexample, contributes to its overall portability.

Turning now to the drawings, there is shown in FIG. 1 an illustrativecutting apparatus 20 in accordance with the present invention forautomatically shearing and bending a chain link of a selected thickness.The apparatus 20 includes a housing 22, a first shearing member 24mounted to the housing 22, a second shearing member 26 pivotally mountedto the housing 22 for movement to exert, in cooperation with the firstshearing member 24, shearing and bending forces upon the chain link, andan electro-hydraulic actuator system 28 cooperating with the secondshearing member 26 to move automatically the second shearing member 26to shear and to bend the chain link, thereby defining an opening in thechain link greater than the thickness of the link.

The housing 22 supplies support for the first and second shearingmembers 24, 26 and the actuator system. The housing 22 also serves tocontain the mechanism in a compact, regularly shaped package easilyadapted to be mounted free standing on legs, or attached directly to apoint-of-purchase chain display unit. Because of typical spacelimitations at the point of use, the size of the housing is desirablyvery compact, for example, approximately one half cubic foot. To providea path for the exchange of outside air with the cavity of the housing, aplurality of vent holes can be disposed in the housing.

The shearing and bending portions 30, 32 of the first and secondshearing members 24, 26, respectively, a key 34 for operating theapparatus 20, and a “dump” valve 36 for resetting the actuator system 28such that the second shearing member 26 is in an open position projectthrough a front cover 38 of the housing 22 for ready access by theoperator.

The first and second shearing members 24, 26 are utilized for theshearing and bending operations described above. The first shearingmember 24 is a stationary shearing member while the second shearingmember 26 is a movable shearing member in the form of a pivotable lever.

Referring to FIGS. 2-4, the first shearing member 24 includes a shearingsurface 40 that defines a shearing plane 41 and terminates in a firstshearing edge 42. The first shearing member 24 includes a generallyU-shaped jaw 43. The jaw 43 has a primary bearing surface 44 to exertshearing and bending forces upon the chain link and a secondary bearingsurface 45 for preventing unrestrained twisting during the shearing andbending operations. The primary bearing surface 44 and the secondarybearing surface 45 are disposed substantially parallel to each other.The jaw 43 defines an opening 46 configured to accommodate the thicknessof the chain link.

The secondary bearing surface 45 and a longitudinal axis 47 of the firstshearing member define a jaw angle 48 that is preferably between about2.5° and about 7.5°, and more preferably about 5°. The shearing surface40 and the primary bearing surface 44 of the first shearing member 24define a rake angle 49 where the primary bearing surface 44 and theshearing surface 40 meet to form the first shearing edge 42 that isslightly less than 90°, preferably between about 88° and about 90°, evenmore preferably about 89°.

Referring to FIGS. 2 and 5, the second shearing member 26 is shown. Thesecond shearing member 26 includes a shearing surface 50 that isdisposed substantially parallel to the shearing plane 41 and terminatesin a second shearing edge 52. The second shearing member includes a jaw53 which has a primary bearing surface 54 and a nip surface 55. Theprimary bearing surface 54 and the nip surface 55 define a jaw angle 57that is preferably between about 85° and about 95°, and more preferablyabout 90°.

The second shearing member 26 includes the primary bearing surface 54 toexert shearing and bending forces upon the chain link. The primarybearing surface 54 is disposed at a first bearing angle 58 relative toan upper edge 59 of the second shearing member 26 that is preferablybetween about 25° and 35°, and more preferably about 30°. The primarybearing surface 54 is preferably disposed at a second bearing angle 60relative to a front edge 61 of the second shearing member 26 that ispreferably between about 55° and 65°, and even more preferably about60°.

The second shearing member includes a power transmission hole 62 and afulcrum hole 63. The transmission and fulcrum holes 62, 63 define alever arm axis 64. The primary bearing surface 54 and the lever arm axis64 define a third bearing angle 65 that is preferably between about 2.5°and 7.5°, and even more preferably about 5°. The upper edge 59 and thelever arm axis 64 define a lever arm angle 66 that is preferably betweenabout 22.5° and 27.5°, and even more preferably about 25°.

Referring to FIG. 6, in a preferred embodiment of the invention, theshearing surface 50 and the primary bearing surface 54 of the secondshearing member 26 define a rake angle 67 where the primary bearingsurface 54 and the shearing surface 50 meet to form the second shearingedge 52 that is slightly less than 90°, preferably between about 88° andabout 90°, and even more preferably about 89°. This configuration servesto assure that, even after minor retouching of the second shearing edge52 should it become dull or chipped, the shearing edge 52 will contactthe material to be sheared prior to contact by the primary bearingsurface 54. This sequence of contact facilitates clean shearing action.

It will be understood that other combinations of angles within thetolerances shown are possible.

Referring to FIG. 2, the second shearing member 26 is pivotally mountedto the housing 22 for movement substantially parallel to the shearingplane 41 as indicated by a pair of arrows 68, 69 in FIG. 2. The secondshearing member 26 is movable between an open position and a range ofcutting positions. The shearing surface 50 of the second shearing member26 is disposed substantially parallel to the shearing plane 41 andterminates in the second shearing edge 52. The primary bearing surface54 of the second shearing member 26 faces in the opposite direction fromthe primary bearing surface 44 of the first shearing member 24. Thesecond shearing member 26 is cooperatively arranged with the firstshearing member 24 for relative shearing action therebetween. Therelative shearing action occurs along the shearing plane 41 between theshearing edges 42, 52 and the primary bearing surfaces 44, 54 of thefirst and second shearing members 24, 26, respectively.

When the second shearing member 26 is in the open position, the firstand second shearing edges 42, 52 of the first and second shearingmembers 24, 26, respectively, are disposed apart from each other. Thetravel of the movable shearing member 26 from the open position to acutting position comprises a cut and open stroke.

In operation, the shearing members 24, 26 cooperate to shear the chainlink along the shearing plane 41. The primary bearing surface 54 and thesecond shearing edge 52 of the second shearing member 26 move toward andbeyond the primary bearing surface 44 and the first shearing edge 42 ofthe first shearing member 24. Shearing the chain link defines a pair ofsevered ends in the chain link. The shearing members 24, 26 cooperate tobend the severed ends apart while the chain link is restrained againstexcessive twisting by the secondary bearing surface 45 of the firstshearing member 24. Bending the severed ends defines an opening betweenthe severed ends of the chain link greater than the thickness of thechain link.

Referring to FIG. 7, a support system 70 is provided to support thefirst and second shearing members 24, 26 and to allow the secondshearing member 26 to rotate. The support system 70 includes a mountingblock 72, a support plate 74, and a main pivot bolt 76. The mountingblock 72 mounts the first shearing member 24 to the housing 22 andsecures the first shearing member 24 in a substantially fixed position.The mounting block 72 is mounted to a first side panel 80 of the housing22 by welds 81 or other fastening techniques, for example.

Referring to FIGS. 7 and 8, the mounting block 72 includes a main bore84 having a counterbore 86 to accommodate the threaded portion of themain pivot bolt 76 and to engage the head of the main pivot bolt 76 toretain it. The mounting block 72 includes first and second mountingbores 88, 89 each having a counterbore 90, 91. First and second mountingbolts 92, 93 extend through the mounting bores 88, 89. The counterbores90, 91 engage the heads of the mounting bolts 92, 93 to retain them. Thethreaded portions of the mounting bolts 92, 93 threadingly engage firstand second tapped mounting holes 94, 95, respectively, of the firstshearing member 24 to secure the first shearing member 24.

Referring to FIG. 7, the support plate 74 is provided to support thepivot bolt 76. The support plate 74 includes a blind, tapped hole 97.The support plate 74 is mounted to a second side panel 100 of thehousing 22 across from the mounting block 72 by welds 101 or otherfastening techniques, for example. The hole 97 of the support plate 74threadingly engages the threaded portion of the pivot bolt 76.

The pivot bolt 76 is provided to serve the dual purpose of securing oneside of the first shearing member 24 and of providing a fulcrum aboutwhich the second shearing member 26 can pivot. The pivot bolt 76 acts asa rod that extends through the second shearing member 26. The pivot bolt76 is supported at each end by the housing 22. The pivot bolt 76 definesone end point of a first lever arm 102 of the second. shearing member26, as shown in FIG. 5. Referring to FIG. 7, the pivot bolt 76 extendsthrough the main bore 84 of the mounting block 72, a main hole 103 ofthe first shearing member 24, the fulcrum hole 63 of the second shearingmember 26, a thrust bearing 104, a flange nut 106, and a jam nut 108 andthreadingly engages the support plate 74.

To minimize the spreading of the shearing members 24, 26 relative toeach other, the thrust bearing 104, the flange nut 106 and the jam nut108 are threaded onto the pivot bolt 76 and are disposed to hold theshearing members 24, 26 between the thrust bearing 104 and the mountingblock 72. A setscrew 110 is disposed in the flange nut 106 toselectively prevent the nut 106 from moving. A setscrew can also besimilarly disposed in the jam nut 108.

In the case where the apparatus 20 is used to cut wire rope having asmall diameter, {fraction (1/32)} inch, for example, the clearancebetween the shearing members 24, 26 becomes an important consideration.The support system 70 allows the clearance between the shearing members24, 26 to be controlled such that wire rope having a diameter as smallas {fraction (1/32)} inch, for example, can be cut.

Referring to FIGS. 9 and 10, in another embodiment of the supportsystem, an L-shaped wall member 115 acts as a keeper and is disposedsuch that the shearing members 24, 26 are disposed between the mountingblock 72 and the wall member 115. The wall member 115 is mounted to thesecond side panel 100 and a top panel 116 of the housing 22 by welds 117or other fastening techniques, for example. The wall member 115 isprovided to further retain the shearing members 24, 26 in acooperatively shearing relationship. The wall member 115 includes a hole119 to accommodate the main pivot bolt 76 and the thrust bearing 104. Awasher 121, which is integral with the flange nut 106, is disposedadjacent the thrust bearing 104 to distribute the tightening forceapplied by the jam nut 108. A setscrew 123 is threaded through themounting block 72 and engages the head of the pivot bolt 72 to preventthe unintentional rotation of the pivot bolt 76. The support systemshown in FIGS. 9 and 10 is similar in other respects to theabove-described support system 70 shown in FIGS. 7 and 8.

Referring to FIGS. 11 and 12, the electro-hydraulic actuator system 28is provided to cooperate with the second shearing member 26 and isselectively operable to move automatically the second shearing member 26between the open position and a cutting position to generate theshearing and bending action between the primary bearing surfaces 44, 54of the first and second shearing members 24, 26, respectively. Theactuator system 28 is selectively operable to move automatically thesecond shearing member 26 relative to the first shearing member 24 toshear and bend the chain link to define an opening in the chain linkgreater than the thickness of the chain link. The actuator system 28moves the second shearing member 26 smoothly and consistently through asubstantially uniform stroke. The actuator system 28 requires nopriming.

The actuator system 28 includes a hydraulic cylinder 130, a pump 132, areservoir 134, and an electric motor 136. The hydraulic cylinder 130 iscooperatively arranged with the second shearing member 26 such that thecylinder 130 is operable to move the second shearing member 26 to acutting position to cut the chain link or cable. The pump 132 is fluidlyconnected to the cylinder 130 for driving the cylinder 130. Thereservoir 134 has a quantity of hydraulic fluid. The pump 132 is fluidlyconnected to the reservoir 134 for drawing the hydraulic fluid from thereservoir 134 and pumping the hydraulic fluid under pressure to thehydraulic cylinder 130. The motor 136 is operatively connected to thepump 132 for selectively driving the hydraulic cylinder 130. The motor136 selectively powers the pump 132, which in turn drives the hydrauliccylinder 130.

The cylinder 130 is a single-action type cylinder, such as a seven-tonsingle acting type, for example. The hydraulic cylinder 130 has a base140 and a driving rod 142 with a distal end 144. The driving rod 142 ismovable between a retracted position and an extended position, having a4½ inch stroke, for example.

To allow the cylinder 130 to articulate with its stroke, the base 140 ofthe cylinder 130 is pivotally mounted to a base clevis 146, which is inturn mounted to the housing 22. A rod clevis 148 is mounted to thedistal end 144 of the driving rod 142. A pivot end 150 of the movableshearing member 26 is pivotally mounted to the rod clevis 148 by a pin152. The pin 152 at the pivot end 150 and the pivot bolt 76 disposed inthe fulcrum hole 103 define a lever arm of the second shearing member26.

The driving rod 142 of the hydraulic cylinder 130 operates upon thelever arm for producing the shearing action between the first and secondshearing members 24, 26. The driving rod 142 moves the movable shearingmember 26 between the open position and a cutting position. When thedriving rod 142 is in the retracted position, the movable shearingmember 26 is in the open position. When the driving rod 142 is in theextended position, the movable shearing member 26 is in a cuttingposition.

A pair of return springs 160, 162 is cooperatively arranged with thecylinder 130 to bias the driving rod 142 to the retracted position,thereby positioning the movable shearing member 26 in the open position.Each spring 160, 162 includes a pair of ends 164, 166 which arerespectively mounted to the distal end 144 of the driving rod 142 at therod clevis 148 and to the base 140 of the cylinder 130.

To spread the force loading associated with the cylinder 130 over alarger area to minimize deflection of the housing 22, a cylinder baseplate 169 is provided. The base plate 169 is mounted to the housing 22and is disposed between the base 140 of the hydraulic cylinder 130 andthe base 168 of the housing 22

The entire hydraulic system is closed. In operation, the pump 132 drawsan amount of hydraulic fluid from the reservoir 134 and pumps the fluidunder pressure to the hydraulic cylinder 1130 on the power strokethereof, thereby moving the driving rod 142 to the extended position.The springs 160, 162 elongate and urge the driving rod 142 to theretracted position. The spring force acts to return the driving rod 142to the retracted position, which in turn forces the hydraulic fluid backinto the reservoir 134. The electro-hydraulic actuator system 28 movesthe second shearing member 26 smoothly and consistently through asubstantially uniform stroke at a substantially steady rate to allow theshearing members to deliver a substantially constant force.

The motor 136 is electrically operated and is provided to drive the pump132. The electric motor 136 can be a ¼ Hp motor that operates on 115VAC, 60 Hz, single phase power, for example. The ready availability ofsuch power facilitates the installation and portability of the apparatus20. The motor 136 includes an internal auto-reset thermal overloadprotection device as an added safety feature. In other embodiments, themotor can be a type that operates on DC voltage.

Because the electro-hydraulic actuator system 28 moves the secondshearing member 26 relative to the first shearing member 24, theshearing member 26 can move at a rate substantially above the cuttingmembers of manually-pumped prior art cutting devices. It has beendetermined through experimentation that the cutting speed at which thesecond shearing member 26 moves is an important design consideration inmaintaining the cutting edge and fracture resistance of the shearingmembers 24, 26 when the apparatus 20 is used to cut hardened chain. Theactuator system 28 can be configured to drive the second shearing member26 at a selected rate. The hydraulic cylinder 130 drives the shearingand bending portion 32 of the second shearing member 26 preferably belowa speed of about 0.2 inches per second, more preferably at a speed ofabout 0.10 inches per second, and even more preferably at a speed ofabout 0.096 inches per second.

To provide a safety feature for the user and to provide full control ofthe operation of the chain cutting apparatus 20, a key-activated switch170 is mounted to the housing 22 and electrically arranged with themotor 136. The switch 170 allows for selective operation of the motor136. The key-activated switch 170 is movable by the key 34 between anoperating position, in which the motor 136 is running to operate thechain cutting apparatus 20, and an off position, in which the motor 136is shut off, thereby stopping the chain cutting apparatus 20. Thekey-activated switch 170 is configured such that the switch 170 isbiased to the off position by a spring, for example. When the switch 170is in the operating position, releasing the key 34 allows the switch 170to return to the off position, thereby ceasing the cutting operation.The key-activated switch 170 can help provide a further safety featureby limiting the use of the chain cutting apparatus 20 to onlyauthorized, trained personnel.

Referring to FIG. 13, the key-activated switch 170 is part of anignition system 172 for electrically operating the motor. The switch 170is electrically connected to a plug 174 that can be mated to an outletin a standard convenience receptacle. A relay 176 and a condenser 178are electrically connected to the plug 174 and the motor 136, therebyforming a circuit 180 between the switch 170 and the motor 136. Uponmovement of the switch 170 to the operating position, the circuit 180 isclosed, thereby allowing electricity to flow to the motor 136, which inturn starts to operate. Releasing the key 34 allows the switch 170 tomove to the off position, which in turn opens the circuit 180, therebyinterrupting the flow of electricity to the motor 136. Accordingly, themotor 136 stops running.

In other embodiments of the apparatus including an electro-hydraulicactuator system having a DC motor, the relay 176 and the condenser 178of the circuit 180 can be replaced with a comparable AC/DC rectifier.

To operate the apparatus 20, the operator obtains the key 34 for theswitch 170. A chain or cable for cutting is selected and placed in thejaw 43 of the first shearing members 24. The chain link can bepositioned such that a portion of the chain link extends through theshearing plane 41. An eye guard can be placed over the shearing andbending portions 30, 32 of the first and second shearing members 24, 26.The operator inserts the key 34 into the switch 170 and rotates the key34 to the operating position. The operator holds the key 34 in theoperating position to operate the apparatus 20 so that the secondshearing member 26 undergoes its cut and open stroke. When the selectedchain or cable is cut and opened, the operator relaxes his hold on thekey 34, thereby allowing the switch 170 to move to the off position.When the switch 170 is in the off position, the motor 136 stops runningwhich ceases the cut and open stroke of the second shearing member 26.

The internal bypass of the hydraulic cylinder 130 is opened momentarilyby opening the dump valve 36 to release any residual hydraulic fluidpressure acting upon the driving rod 142, thereby allowing the springs160, 162 to position the driving rod 142 to its fully retractedposition, thereby moving the second shearing member 26 to the openposition, as shown in FIG. 13. It should be noted that the driving rodstroke can be minimized by designing the various components andpositioning them in such a manner that the fully retracted driving rod142 defines the clockwise limit of travel of the second shearing member26.

When the driving rod 142 is in the retracted position, the chain cuttingapparatus 20 is ready to accept the next selected chain link or cablefor cutting. The operator can remove the cut link or cable from thefully open jaws. The key 34 for the switch 170 can be returned to itscontrolled storage location.

Referring to FIG. 5, the illustrative first lever arm 102 has a lengthof 5.5 inches. An illustrative second lever arm 190 has a length of1.625 inches. In embodiments of the chain cutting apparatus having suchlever arms 102, 190 and a hydraulic cylinder that delivers a forcebetween about 6,000 and about 14,000 lbs. at a rate of about 0.330inches per second, the jaw 55 of the second shearing member 26 candeliver a shear force between about 20,310 and about 47,404 lbs. at arate of about 0.096 inches per second.

The first and second lever arm lengths 102, 190 of the second shearingmember 26 and the stroke of the driving rod are selected to cause theprimary bearing surface 54 of the second shearing member 26 to move pastthe primary bearing surface 44 of the first shearing member 24 tocontinue bending the link after it has been severed, as shown in phantomlines in FIG. 12.

It will be appreciated that the shearing members are preferably ofsubstantial width for at least two reasons. First, the high stresses towhich the members are subjected require that the members have sufficientstrength to perform the above described shearing and bending operationswithout permanent distortion which would impair the subsequent operationof the apparatus. Second, the bearing surfaces must be of sufficientarea to assure that they positively engage the severed ends of the linkbeing cut and bent apart.

On the other hand, shearing members of excessive width increase both thecost and weight of the apparatus. It is preferable, but not essential,that the members be of substantially equal width so that they actsimilarly on both severed ends of the link. It will be understood thatin other embodiments the width of the shearing members can vary.Satisfactory results have been achieved using ¾ inch wide steel shearingmembers to cut and open ⅜ inch products and 1 inch wide shearing membersto cut and open ½ inch products.

The distribution of mass in both the first and the second shearingmembers to provide adequate tensile strength at the points of higheststress and shock is important to maintaining shearing member integrity.The shearing members are configured to provide an adequate amount ofmass and cross section at high stress points to give the necessarystrength for fracture and cracking resistance. The points of higheststress are located above the jaw on the second, movable shearing memberand below the jaw on the first, stationary shearing member. It has beendetermined that the movable shearing member made from solid tool steelhas a critical mass with a minimum cross section of 1.65 in.² forembodiments of shearing members having a ¾ inch width and of 2.24 in.²for embodiments of shearing members having a 1 inch width. Thestationary shearing member made from solid tool steel has a criticalmass with a minimum cross section of 1.46 in.² for embodiments ofshearing members having a ¾ inch width and of 2.10 in.² for embodimentsof shearing members having a 1 inch width.

In other embodiments, the shearing members can be made with hardenedtool steel inserts that are secured with dowel pins of other fasteningmeans. The hosting body for such an embodiment can be a hardened highcarbon steel.

The shearing members can be made from any suitable tool steel, forexample, such as O1, S-7, M-2, D-2, A-2, or A-6. Preferably the materialof the shearing members is tough enough to withstand the shock ofshearing and snapping hardened chain links and is durable enough tocontinue to maintain a keen shearing edge over many cuts. To maximizeshock resistance, performance, and cutting edge durability, the shearingmembers are preferably made from S-7 tool steel, hardened to 59-60 Rc,and double tempered.

The mechanical advantage achieved through the use of the actuator systemand the lever arm enables large gauge chain to be easily cut. Theapparatus 20 is designed to create an opening between the severed endssufficient to allow the sheared and bent link to be removed from theadjacent intact links. As explained above, throughout the shearing andbending operations the secondary bearing surface 45 of the firstshearing member 24 bears upon the link to prevent excessive twisting ofthe link which might otherwise result. The twisting, if unrestrained,would impair the capacity of the apparatus to generate a sufficientopening through which the adjacent intact links could be removed. Theapparatus can cut chain links as large as ½ inch thick made from grade100 metal, for example, and can cut wire rope as small as {fraction(1/32)} inch, for example.

From the above detailed description, it is clear that under normaloperating conditions, the apparatus should require little maintenance.Adjusting the support system 70 can readily compensate for any wearbetween the shearing members 24, 26. Should the shearing edges 42, 52become worn or chipped, the shearing members 24, 26 may be readilyremoved for sharpening or replacement. Such measures should be requiredinfrequently, however, as the machine is protected against harmresulting from excessive strain through the safeguard of spacing primaryand second bearing surfaces 44, 45 of the first shearing member 24 toaccept only chains of manageable size.

It is also apparent from the description and drawings that bolts, cable,and other items having small cross sections can be sheared with theapparatus. The overtravel of the primary bearing surface 54 of thesecond shearing member 26 beyond the primary bearing surface 44 of thefirst shearing member 24, utilized to open a chain link after it hasbeen severed, is superfluous for these operations.

In addition, it will be understood that the chain cutting apparatus canbe operable with longer or shorter shearing members, faster or slowerpumps creating different hydraulic pressures, and different cylindershaving different cylinder bores and strokes. Hydraulic valves and otherdevices, such as, flow controls or pressure switches, for example, canbe manually or electrically actuated. Limit switches can be used toprevent overtravel. Double-acting cylinders can be used instead of theillustrative single-acting, spring-return cylinder. Various combinationsof these components are possible in other embodiments of the chaincutting apparatus of the present invention.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. Recitation of ranges of values herein are merely intended toserve as a shorthand method of referring individually to each separatevalue falling within the range, unless otherwise indicated herein, andeach separate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate the invention and does not pose alimitation on the scope of the invention unless otherwise claimed. Nolanguage in the specification should be construed as indicating anynon-claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention. Ofcourse, variations of those preferred embodiments will become apparentto those of ordinary skill in the art upon reading the foregoingdescription. The inventors expect skilled artisans to employ suchvariations as appropriate, and the inventors intend for the invention tobe practiced otherwise than as specifically described herein.Accordingly, this invention includes all modifications and equivalentsof the subject matter recited in the claims appended hereto as permittedby applicable law. Moreover, any combination of the above-describedelements in all possible variations thereof is encompassed by theinvention unless otherwise indicated herein or otherwise clearlycontradicted by context.

1. An apparatus for automatically shearing and bending a chain link, thechain link having a selected thickness, the apparatus comprising: afirst shearing member, the first shearing member having a shearingsurface defining a shearing plane and terminating in a first shearingedge, the first shearing member including a jaw, the jaw having aprimary bearing surface to exert shearing and bending forces upon thechain link and a secondary bearing surface for preventing unrestrainedtwisting during the shearing and bending operations, the jaw defining anopening, the opening configured to accommodate the thickness of thechain link; a second shearing member, the second shearing member havinga shearing surface disposed substantially parallel to the shearing planeand terminating in a second shearing edge, the second shearing memberincluding a primary bearing surface to exert shearing and bending forcesupon the chain link, the second shearing member arranged with the firstshearing member for relative shearing action along the shearing planebetween the shearing edges and the primary bearing surfaces; and anelectro-hydraulic actuator system cooperating with the second shearingmember, the actuator system selectively operable to move automaticallythe primary bearing surface and the second shearing edge of the secondshearing member toward and beyond the primary bearing surface and thefirst shearing edge of the first shearing member to shear the chain linkalong the shearing plane, thereby defining a pair of severed ends in thechain link, and to bend the severed ends apart while the chain link isrestrained against excessive twisting by the secondary bearing surfaceof the first shearing member, thereby defining an opening between thesevered ends of the chain link greater than the thickness of the chainlink, the actuator system being electrically operated and requiring nomanual actuation force input.
 2. The apparatus as set forth in claim 1wherein the shearing surface and the primary bearing surface of thesecond shearing member define a rake angle that is slightly less than90° where the primary bearing surface and the shearing surface meet toform the first shearing edge.
 3. The apparatus as set forth in claim 2wherein the rake angle is about 89°.
 4. The apparatus as set forth inclaim 1 wherein the second shearing member includes a jaw, the jawhaving a nip surface and the primary bearing surface, the nip surfaceand the primary bearing surface defining a jaw angle that is betweenabout 85° and about 95°.
 5. The apparatus as set forth in claim 4wherein the jaw angle is about 90°.
 6. The apparatus as set forth inclaim 1 wherein the second shearing member includes first and secondholes which define a lever arm axis, the primary bearing surface and thelever arm axis defining an angle that is between about 22.5° and about27.5°.
 7. The apparatus as set forth in claim 6 wherein the firstcutting edge angle is about 25°. 8-10. (canceled)
 11. The apparatus asset forth in claim 1 wherein the primary bearing surface of the secondshearing member faces in the opposite direction from the primary bearingsurface of the first shearing member.
 12. The apparatus as set forth inclaim 1 wherein the electro-hydraulic actuator system is electricallyoperated.
 13. The apparatus as set forth in claim 1 wherein theelectro-hydraulic actuator system is hydraulically actuated.
 14. Theapparatus as set forth in claim 12 wherein the electro-hydraulicactuator system is hydraulically actuated.
 15. The apparatus as setforth in claim 14 wherein the electro-hydraulic actuator system includesa hydraulic cylinder and an electric motor for selectively driving thehydraulic cylinder.
 16. An apparatus for automatically shearing andbending a chain link, the chain link including a selected thickness, theapparatus comprising: a housing; a first shearing member mounted to thehousing; a second shearing member pivotally mounted to the housing formovement to exert, in cooperation with the first shearing member,shearing and bending forces upon the chain link; and anelectro-hydraulic actuator system cooperating with the second shearingmember to move automatically the second shearing member to shear and tobend the chain link, thereby defining an opening in the chain linkgreater than the thickness of the link.
 17. An apparatus forautomatically shearing and bending a chain link, the chain linkincluding a selected thickness, the apparatus comprising: a housing; afirst shearing member mounted to the housing; a second shearing member,the second shearing member pivotally mounted to the housing for movementsubstantially parallel to the shearing plane, the second shearing memberarranged with the first shearing member for relative shearing actionbetween the first and second shearing members; and an electro-hydraulicactuator system cooperating with the second shearing member, theactuator system selectively operable to move automatically the secondshearing member relative to the first shearing member to shear the chainlink and to bend the chain link to define an opening in the chain linkgreater than the thickness of the chain link, the actuator systemrequiring no manual actuation force input, the actuator system includinga hydraulic cylinder, a pump, and a motor, the hydraulic cylindermounted to the second shearing member for movement thereof, the pumpfluidly connected to the hydraulic cylinder for driving the hydrauliccylinder, and the motor operatively connected to the pump forselectively driving the pump.
 18. The apparatus as set forth in claim 17wherein the actuator system further comprises a reservoir, the hydrauliccylinder having a base and a driving rod with a distal end, the basepivotally mounted to the housing, the distal end of the rod mounted tothe second shearing member for moving the second shearing member, thedistal end of the rod mounted to the second shearing member for movingthe second shearing member, the reservoir having a quantity of hydraulicfluid, the pump fluidly connected to the reservoir for drawing thehydraulic fluid from the reservoir and pumping the hydraulic fluid underpressure to the hydraulic cylinder.
 19. The apparatus as set forth inclaim 18 wherein the actuator system includes a spring for biasing thesecond shearing member to an open position wherein the first and secondshearing edges are disposed apart from each other.
 20. The apparatus asset forth in claim 19 wherein the spring includes a pair of ends, theends being mounted to the base of the cylinder and the distal end of therod.
 21. The apparatus as set forth in claim 18 wherein the secondshearing member is in the form of a lever and includes a pivot end, thechain cutting apparatus includes a rod extending through the secondshearing member and supported at each end by the housing, the rod beinga fulcrum for the second shearing member, the pivot end and the roddefining a lever arm of the second shearing member, and the driving rodof the hydraulic cylinder operates upon the lever arm for producing theshearing action between the first and second shearing members. 22-27.(canceled)
 28. The apparatus as set forth in claim 27 wherein the secondshearing member is driven by the hydraulic cylinder at a speed of about0.096 inches per second.
 29. The apparatus as set forth in claim 17wherein the actuator system further comprises a dump valve for resettingthe actuator system such that the second shearing member is in an openposition. 30-32. (canceled)